37G CLASS CRUSTACEA. 



enlarged thigh, terminated by a strong claw. The second and 

 third segments are almost lunulated, and support, each, a pair 

 of feet, formed of a single articulation, terminated by two sorts 

 of digits, denticulated at the end. To the fourth segment is 

 attached another pair of feet, the fifth and last, but in the form 

 of simple, oval vesicles, divergent, and immoveable, and which 

 Hermann presumes to be ovaries, rather than feet. Both this 

 segment and the following are almost square ; the sixth is 

 much longer and cylindrical ; tlie seventh and last is three 

 times shorter, almost orbicular, flatted, and terminated by two 

 small vesicles. The eyes are not distinct. 



Dichelestium Stiirionis, Hermann, fils, Mem. Apterol, 

 page 125, v. 7, 8; Desmar. Consid., L. v., is about seven 

 lines in length, and one in breadth. The second segment, 

 lengthened on each side into an obtuse papilla, and the follow- 

 ing four are red, and of a whitish-yellow laterally. The feet 

 do not appear when the animal is viewed from above. It 

 insinuates itself deeply into the skin, and covers the osseous 

 arches of the gills, but without fixing itself, as would appear, 

 on their combs. Hermann has collected as many as a dozen 

 from a single fish. Two or three of this number, males, per- 

 haps, were one-third shorter than the others, and had a curved 

 body ; one of these twelve individuals lived for three days. 

 These Crustacea turn round fi'cquently, and with vivacity ; 

 they hook themselves very strongly by means of their frontal 

 forceps. 



NicoTHOE, Aud. and Miln. Edw., 



Terminate the class of Crustacea, and are distinguished from 

 the rest by their heteroclite form. They present, on a simple 

 view, nothing but a body formed of two lobes, united in the 

 manner of a horse-shoe, and enclosing two others. But when 

 observed through the microscope, we discover that the two 

 large lobes, are laige lateral expansions of the thorax, in the 



